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FreeBSD-SA-02:19                                            Security Advisory
                                                                FreeBSD, Inc.

Topic:          squid heap buffer overflow in DNS handling

Category:       ports
Module:         squid24
Announced:      2002-03-26
Credits:        zen-parse <zen-parse@gmx.net>
Affects:        squid port prior to version 2.4_9
Corrected:      2002-03-22 00:19:55 UTC
FreeBSD only:   NO

I.   Background

The Squid Internet Object Cache is a web proxy/cache.

II.  Problem Description

Incorrect handling of compressed DNS responses could result in a
heap buffer overflow.

The squid port is not installed by default, nor is it "part of
FreeBSD" as such: it is part of the FreeBSD ports collection, which
contains thousands of third- party applications in a ready-to-install
format. The ports collection shipped with FreeBSD 4.5 contains this
problem since it was discovered after the release.

FreeBSD makes no claim about the security of these third-party
applications, although an effort is underway to provide a security
audit of the most security-critical ports.

III. Impact

A malicious DNS server (or an attacker spoofing a DNS server) could
respond to DNS requests from squid with a specially crafted answer
that would trigger the heap buffer overflow bug.  This could crash the
squid process.  This bug is not known to be exploitable.

IV.  Workaround

1) Deinstall the squid port/package if you have it installed.

V.   Solution

One of the following:

1) Upgrade your entire ports collection and rebuild the port.

2) Deinstall the old package and install a new package dated after the
correction date, obtained from the following directories:

[i386]
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/www/
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/www/

[alpha]
Packages are not automatically generated for the alpha architecture at
this time due to lack of build resources.

NOTE: It may be several days before updated packages are available.

3) Download a new port skeleton for the squid port from:

http://www.freebsd.org/ports/

and use it to rebuild the port.

4) Use the portcheckout utility to automate option (3) above. The
portcheckout port is available in /usr/ports/devel/portcheckout or the
package can be obtained from:

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/Latest/portcheckout.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/Latest/portcheckout.tgz

VI.  Correction details

The following list contains the revision numbers of each file that was
corrected in the FreeBSD ports collection.

Path                                                             Revision
- -------------------------------------------------------------------------
ports/www/squid24/Makefile                                           1.89
ports/www/squid24/distinfo                                           1.64
- -------------------------------------------------------------------------

VII. References

<URL:http://www.squid-cache.org/Advisories/SQUID-2002_2.txt>
<URL:http://www.squid-cache.org/cgi-bin/cvsweb.cgi/squid/lib/rfc1035.c#rev1.24>
<URL:http://www.squid-cache.org/cgi-bin/cvsweb.cgi/squid/lib/rfc1035.c#rev1.23>

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